Linux is a fairly common operating system with open source source code. It is used in many enterprises, both on work computers and on servers. This is due to the undeniable advantages OS, although it has a number of disadvantages:
Advantages:
- The system is spreading for free, no license required
- Virtually no requirement protection antivirus
- You can find an OS version for a computer of almost any power
Flaws:
- Some versions are very differ from the usual Windows
- Many programs for Windows on Linux does not work
- A small amount of software compared to Windows
- There may be problems with installation drivers
A huge advantage of Linux is the ability install it to a flash drive. To be precise, Windows can also be installed and run on a flash drive, but this will require creating a special image. And Linux has an official portable assembly, which can be downloaded for free from the official website.
Before downloading, you should decide on the system version. If your PC has 2 or more nuclear CPU, and RAM more 2 GB, that makes sense download version for x64 systems. It is more modern and will allow you to realize all the capabilities of a PC, including UEFI support.
Installation on a USB flash drive in Windows
It is assumed that the operating system has already been downloaded from the official website in ISO format. To begin installation, you must obtain a special program. Suitable for these purposes Universal USB Installer.
For installation you will need a flash drive at least 2GB in size.
Let's launch program. 
Let's sort it out settings:
- Step 1 – prompts you to select the type of operating system. In our case it is Ubuntu.
- Step 2 – you need to select the location of the system image
- Step 3 – selecting the drive on which the system will be installed. When you check the We will format as fat32 checkbox, the flash drive will be formatted in Fat32 format
- Step 4 don't touch it, leave the slider as it is.
After pressing the button Create The image will begin to be created, which usually lasts a few minutes. Then the flash drive can be used.
You can use another application UNetbootin. The procedure is not much different from the above:
Installation on Ubuntu
If you need to make a bootable USB flash drive in Linux, then the procedure is approximately the same as in Windows. In this case no third party programs no need to download.
We are looking for a standard utility through the search “ Creation boot disk
». 
In it we indicate path to the pre-downloaded image and installation drive. All you have to do is click on “ Create a boot disk” and the process will begin, which will end with the creation of the necessary drive.
How to run Linux from a flash drive
After the flash drive with the system is ready, it must be run. For this it is necessary change boot order in BIOS. You can get into it by pressing buttons Del, F2 or F12 when the computer boots. If you can’t enter the BIOS, you can see the button you need to press on original loading screen. 
When the flash drive boots, a menu will appear on the screen in which you need to click on TryUbuntuwithoutinstalling. The system will start in mode Live, i.e. without installation.
Check Linux compatibility
When Live USB will boot, you will be able to see the operating system desktop. According to him appearance can be define whether your computer hardware is suitable for this version of the system. Can check drivers to know if all the equipment was installed correctly. 
It is worth noting that working from a flash drive will be noticeably slower, which is due throughput USB. To evaluate the operation of the OS on your computer, it is best to use virtual machine. One of the most popular is Virtualbox.
We won’t describe the settings, but there shouldn’t be any problems. Intuitive prompts allow you to set up the machine without any problems.
Existing Alternatives
Currently, Ubuntu is not the only free operating system. There are several dozen of them, but we will touch on the most popular:
Debian– an old OS that is constantly evolving. It served as the basis for many similar systems, including Mint and Ubuntu. The disadvantages are that it is designed for advanced users. 
openSUSE– is also a fairly popular system. The advantage is the built-in YAST software package for system configuration. 
LinuxMINT– one of the most popular systems, not inferior to Ubuntu. It features a user-friendly interface similar to Windows, which makes it convenient for novice users. 
Linux feels great on flash drives and external drives. So if you want to try new distribution or just start getting acquainted with Linux, then installing on an external drive is a good option (even easier to work with).
By installing Linux on USB you will get portable system, which can be downloaded on another computer.
Unlike virtual computers, the system on a flash drive has full access to the hardware (built-in Wi-Fi adapter, video card, etc.) - thanks to this you can use the computer's resources to their full potential.
When installing and using Linux on an external drive, not entirely obvious problems may arise - in this instruction I will show you how to solve them.
By the way, precisely with possible problems let's get started.
BIOS and EFI
Then on startup virtual machine connect your flash drive or your USB disk to the real computer, and then connect it to the virtual machine:
So, the first option
choose Manual disk partition:
There may be some sections:
If you don't need them, delete them all, you'll get:
Now select Automatic marking:
Auto - use the entire disk:
Specify drive:
Leave it as is if you don't know how to use it:
If you install with EFI, then similar markup will be created:
Please note that section ESP must be required - without it, EFI simply will not see your disk. This is a small partition in FAT32 where the bootloader is located. At your discretion, you can edit other partitions, for example, I removed the swap file and reduced the disk size:
We agree with the requests of the installer, who can warn about the absence of a swap file. Confirm the selected disk layout:
I repeat once again that this method always leads to a failure for me if the disk is not empty - the installer cannot cope with the partitioning of a non-empty disk.
Therefore there is a second option.
At the very beginning, when we get to the download, select Live Mode instead of the installer. When the system boots into Live mode, connect your flash drive/disk to the real computer, and then connect it to the virtual one, if you have not done so before.
Use the following command to check the disk name:
Sudo fdisk -l
It should be /dev/sda
Let's do a complete cleanup of the /dev/sda flash drive. Just in case: a complete wipe means that ALL DATA from the flash drive will be DELETED! Please note that we do this IN A VIRTUAL MACHINE. Do not do this on a real computer, if you do not understand what name your flash drive has, you will erase the first (most likely system) disk.
Open it with the program gdisk:
Sudo gdisk /dev/sda
To switch to expert mode, enter
Then to remove GPT enter
Agree twice to completely clear the drive.
Reboot the virtual computer:
At the next boot, select the option to install the system - then proceed as usual.
How to install Linux on a flash drive or USB drive
Using the method described above, you can also install Linux on USB directly on a physical computer, without using VirtualBox. At the same time, be careful not to accidentally confuse the flash drive with some kind of internal drive and erase the information on it.
Also remember the names of the disks after you disconnect the installation flash drive. For example, in this photo, the installation flash drive (sdb) comes first, followed by the external USB drive on which I want to install (sdc):
If you continue the installation, you will then have to rename the disk in the bootloader. I did it simpler, turned off the computer and swapped the flash drive and disk in the USB sockets, it turned out like this:
Now even after disconnecting installation flash drive, the USB disk with the system will still have the name sdb and you won’t have to configure anything additional.
Booting Linux from USB from VirtualBox (BIOS)
By the way, this method turned out to be very useful for me: some systems, for example Parrot, do not boot on the physical computer after installation. The problem is solved by booting from this disk via VirtualBox and updating the system. After this, the system is able to boot on a physical computer. Some Kali Linux users also complain about similar problems (the Live system works great, but after installation the system does not boot). Apparently, the issue is some kind of incompatibility with hardware, which is corrected in new versions of the kernel.
Boot Linux from USB from VirtualBox (EFI)
VirtualBox has its own peculiarities with EFI. First, you need to start downloading from external drive as described in this article.
That is, it will be output UEFI Interactive Shell, there will also be a message “ Press ESC in 1 second to skip startup.nsh or any other key to continue».
The reason for the error is that the VirtualBox EFI bootloader does not see the files .efi to continue loading the OS.
There are two options to solve this problem:
1) explicitly indicate to the loader the necessary files
2) change the name of the required files to default ones - which the bootloader will definitely find.
1. Specify the .efi file to the bootloader:
In the invitation
dial:
Now run the command
to see the contents of the folder EFI:
We see a folder there parrot, now let's see what's inside this folder:
Dir EFI\parrot
So, we see the file there grubx64.efi. It turns out that the file that the system cannot find is located on the path \EFI\parrot\grubx64.efi
Open the file for editing:
Edit startup.nsh
And enter the line there (you may have another one, for example, \EFI\Manjaro\grubx64.efi or some other options):
\EFI\parrot\grubx64.efi
To save:
Ctrl-s
To exit the editor:
Ctrl-q
To reboot:
After this, the system will boot normally:
2. Change file names to fault-tolerant ones
As we just saw, the file to download is located in the path /EFI/parrot/grubx64.efi, the failsafe name that the system looks for by default is /EFI/BOOT/BOOTX64.EFI
You can open this drive and simply rename the folder and file to /EFI/BOOT/BOOTX64.EFI- the system will boot and this will not affect anything else.
Installing multiple Linux distributions on one USB
Nothing prevents you from installing a second one on a USB drive Linux distribution, as well as the third, fourth, fifth and so on.
The process is always approximately the same - a new partition is created from (part of) free space and a new distribution is installed on it.
Linux boot loader detects neighboring systems well
and when the computer starts, it offers a choice of booting from one of them.
There may be different nuances with “friendly” distributions. For example, Ubuntu pretends to be Windows and doesn't want to install on USB. Everything can be solved by connecting the disk in a special way as described in this article.
This same Ubuntu does not allow you to manually set the disk size and takes up all the free space...
By using GParted Ubuntu cured of greed:
In general, if you want to take a “step left, step right,” then “friendliness” immediately turns into a headache.
Why Linux won't boot from USB
In addition to the options already listed, when problems may arise, also check whether the options are disabled in your EFI settings Security Boot And Fast Boot.
Iron
- try not to use USB hubs - they cause a lot of problems
- During installation, do not move the flash drives or drive wires.
- Flash drives can turn off due to overheating - remember this
You might find this useful:
I bought myself two of these SATA-USB adapters. First :
Supports USB 3.0, I inserted a 2.5 inch into it SSD drive from an old laptop - it works really fast! About the size of a palm or the size of a modern day mobile phone. The case is transparent, the drive can be installed without a screwdriver or screws - however, I have doubts whether it can be pulled out later without damaging the contacts... I bought it from this seller. 6 bucks, Carl!
And I bought this one at a local store (600 rubles), it only supports USB 2, noticeably slower than the previous one, and it comes with a nice case. I inserted it into HDD drive(also from an old laptop):
Correct installation of Ubuntu from a flash drive will provide the ability to work on a computer or laptop in an operating system that provides legal free use most programs and the platform itself, unlike Windows, which is distributed free of charge or through “pirated” distributions.
Linux also has other advantages that the user will receive after installing Ubuntu. And this will not take much time and following a few simple recommendations.
Benefits of installing from a USB drive
By installing Ubuntu OS from a flash drive, the user receives a number of advantages compared to installing the distribution kit on a CD or DVD:
- The ability to install the system on a device without a disk drive (which may, for example, be broken or absent altogether, as in some modern PCs, almost all netubes or nettops);
- High installation speed, since USB 2.0 and 3.0 flash drives are much faster compared to disks;
- No problems accessing information due to scratched disk surfaces.
Creating a USB flash drive for installing Ubuntu
Before you install operating system on your computer, you should first download its distribution from a reliable site and install it on a flash drive, converting it to a suitable ISO format.
If you already have a system image, you should burn it to media.
The distribution kit already available on the flash drive will further simplify the procedure, but, as a rule, only occupy it installation program ineffective - it's easier to store Ubuntu on your computer's hard drive.
Or on the same media, but configured not for loading, but for storing information - the distribution kit does not exceed 2 GB in size and can be freely located on media formatted in FAT32.
1. Download the distribution
Downloading the distribution kit will not take much time - you can find more or less modern versions on the websites Ubuntu.com or Ubuntu.ru.
Today, one of the most current systems is Ubuntu 14.04.
You can also find older versions here, but the computer resource requirements for Linux are not as different for the different options as for Windows.
And the latest platforms have more functionality.
2. Create a boot disk in Windows
Then insert the device into the USB port, restart the computer and begin the installation.
Another option is to call the boot menu when the computer boots (by pressing Esc, F2, F8 or one of the other function keys top row) and select boot from media.
Download Ubuntu Live
Distribution Ubuntu Desktop is an operating system that boots in Live mode, that is, without the need for installation on a PC.
In this case, the functionality of the platform will be approximately the same.
However, it is more convenient to work in the system when the system files are still on the hard drive.
Immediately after bootable flash drive automatically launched, a window will appear on the screen asking you to first select the language with which the user prefers to work, and then the appropriate launch or installation mode:
After selecting the second option and Russian (or English, if that is more convenient for some purposes, or any other) language, a new window opens called “Preparing to install Ubuntu.”
Here you will see how much space there is on the partitions hard drive where the system will be installed, and whether there is an Internet connection - usually it is turned off during installation, but all updates for Ubuntu can be downloaded later.
The menu also suggests installing a third-party software, if it is built into the distribution (codecs for sound playback, etc.).
The next step is to select an installation option. Among them there is the possibility:
- Install the system, leaving the platform already available on the computer (for example, Windows) operational;
- Replace the old system with a new one;
- Carry out an installation with the ability to encrypt records to increase the level of security of working on the computer;
- Label the disks yourself, completely changing their existing sizes.
Advice! In most cases, for users who have just started working with Linux Ubuntu, you should choose the first option. Experienced users are advised to select the second or last menu item.
Selecting the hard drive partition size
When choosing to install two operating systems simultaneously, the next window shows the sizes of the HDD partitions. Here you can choose which part of them will be occupied by the new OS, and which will remain assigned to the old one.
And, although you can partition a disk using special partition editors, it is better to do this by moving the separator between volumes.
In the example shown, one of the disks has a size of 16 GB. At the same time, most of it (9.5 GB formatted in NTFS) will be given to the Windows OS, and 6.5 GB with the ext4 file system will be able to be used by Ubuntu.
Today, installing a full-fledged and modern version (14.04) will take relatively little, about 10 GB.
However, there is a condition - when installing on top of Windows, another 4-5 GB is required for the swap partition, where the contents of RAM will be temporarily written when Ubuntu is running.
In addition, Linux, if a second system is left, should occupy 2 partitions.
And on physical disk, already divided into 3-4 parts, there is no such possibility (the number of logical drives should not exceed 4).
In this case, you will have to create a separate partition to install the operating system.
Completing the operating system installation
After selecting “Install now”, a warning will appear about creating additional partitions and resizing old ones.
All this takes quite a lot of time - the more changes, the longer it will take to install the OS.
After installation is complete, the user is offered a choice of regional standards for new system, including language and layout, as well as time zone.
This completes the transfer of Ubuntu from a flash drive to a computer.
Conclusion
After choosing a user name and, if necessary, setting a password, you need to restart the computer.
The boot option selection menu appears again on the screen, requiring you to enter a password.
And after logging into the system for the first time, all that remains is to customize it for yourself by connecting to the Internet, installing the necessary codecs, drivers and programs, depending on the requirements for the functionality of the system.
Almost no one uses disks to install Linux on a PC or laptop anymore. It is much easier to burn the image to a flash drive and quickly install a new OS. In this case, you don’t need to bother with a disk drive that may not exist at all, and you don’t have to worry about a scratched disk either. By following simple instructions, you can easily install Linux from a removable drive.
First of all, you will need a drive formatted in FAT32. Its volume must be at least 4 GB. Also, if you don’t yet have a Linux image, then internet with good speed will come in handy.
Our instructions will help you format the media in FAT32. It talks about formatting in NTFS, but the procedures will be the same, only you need to select the option everywhere "FAT32"
Please note that when installing Linux on a laptop or tablet, this device must be connected to power (to an outlet).
Download image from Ubuntu is better from the official website. There you can always find the current version of the OS without worrying about viruses. The ISO file weighs about 1.5 GB.
Step 2: Create a bootable USB flash drive
It is not enough to simply transfer the downloaded image to a flash drive; it must be written down correctly. For these purposes you can use one of special utilities. Let's take the program as an example. To complete the task, do this:
More details about creation bootable media with Ubuntu, read our instructions.
Step 3: BIOS Setup
In order for the computer to load the USB flash drive when turned on, you will need to configure something in the BIOS. You can access it by clicking "F2", "F10", "Delete" or "Esc". Then follow a series of simple steps:
This procedure is suitable for AMI BIOS; it may differ on other versions, but the principle is the same. Read more about this procedure in our article on setting up the BIOS.
Step 4: Preparing for Installation
The next time you restart your PC, the bootable flash drive will launch and you will see a window with a choice of language and OS boot mode. Then do the following:
A full-fledged operating system on a small external media is very convenient. You can run the system on almost any computer, and also have all your files and data always at hand, and you no longer need to keep a large number of systems on the main drive.
It is for these reasons that many computer users are interested in how to perform Linux installation on a flash drive, is this possible, and if possible, how to implement everything correctly. In this article we will try to answer such questions. We will also analyze in detail the installation process on a flash drive for one of the most popular distributions- Ubuntu.
Despite all the advantages of using an operating system from a flash drive, many say that this is not necessary. And for good reason, because such intensive use of a flash drive can simply destroy it.
Non-volatile flash memory has one significant drawback - it is a limited number of rewrites of one data cell. There are no restrictions on the number of data reads, and the write limit is very significant - tens of millions of times. For using flash drives for their intended purpose, this is not critical, since the recording frequency is not very high and the flash drive lasts a long time.
But when you install the system on a USB flash drive, the kernel, file system, programs constantly save their temporary files, constantly work with data and write something to disk; the situation is further complicated by file system journaling, since it enters data about any file changes into the journal, which further increases the number of rewrites of flash drive blocks.
You can say that there are SSDs made using the same technology that are used in computers. But everything is not entirely true, SSDs are designed for such a load, because they have a rewrite limit of several billion, as well as the ability to hot-swappable already failed blocks with backup ones.
Therefore, when you agree to install an operating system on a flash drive, you must understand that the flash drive will work much less than it could. But it's not all bad, you can perform some optimizations that will force the system to write less information to disk. If you agree with the risk, then next we will look at how to install Linux on a flash drive.
Installing Linux on a USB flash drive
operating room Linux system allows the user to do everything he needs, and if you want Linux on a flash drive, then that’s possible too. We don't even have to resort to any special tools.
We will consider the entire process using Ubuntu as an example, and everything will be done using the official installer. We will not be interested in simply writing an image to disk or working from RAM. In the end, we will get a full-fledged operating system on a flash drive.
First, do everything as usual, select the language, software and update settings. The differences begin at the disk marking stage. Here you need to choose the manual option, because automatic marking does not allow us to do what we need.
There will be one note here, you need to ensure that the system is not loaded from the flash drive on which you are going to install it, otherwise you will not be able to install ubuntu on the flash drive. That is, in addition to the installer, another clean flash drive must be connected to the system. If everything was done correctly, then in addition to the main disk /dev/sda, the /dev/sdb flash drive will appear in the layout window:
For a flash drive, its size, disk label will be indicated, and most likely there will be only one partition on it. This partition must be deleted to gain free space.
The first partition must be created with the FAT32 file system and precisely the first one so that Windows can work with it. For example, if you have a 16 GB flash drive, then 5-4 GB can be allocated for data. The mount point for this partition is /home:
The second section applies to system files, here we need at least eight gigabytes. It’s better to use Btrfs as a file system, since we don’t need journaled ext4, and btrfs has compression and optimization for ssd. Specify / as the mount point:
The last action at this step of the wizard is to specify the device for the bootloader, this should be the same flash drive on which you are installing the system.
Optimizing Ubuntu for working on a flash drive
Installing Ubuntu on a flash drive is complete, but now we just need to make it work in such a way as to write data to the disk as little as possible. All this must be done in an already installed system.
Most of the settings will be carried out in the /etc/fstab file, first we will enable compression of all files and optimization for ssd in btrfs, which is used as the root. We used the /dev/sdb2 partition for the root, since we used /dev/sdb1 for /home:
/dev/sdb1 / btrfs errors=remount-ro,noatime,nodiratime,compress=lzo,ssd,commit=60 0 1
Perhaps your disks in fstab will be named by UUID, then you will have to find the entry that indicates the mount point / and the btfs file system, and therefore change it. Let's look at the options:
- errors=remount-ro- remount read-only during errors;
- noatime- do not update file access time;
- nodiratime- do not update folder access times;
- compress=lzo- use lzo compression, this is the fastest zlib algorithm gives a higher compression ratio but takes longer;
- commit=60- by default, the file system writes all information about file changes every 30 seconds to disk, but using this parameter you can specify your own value, but not more than 300;
- ssd- a set of optimizations for solid-state drives.
Some folders in which temporary system files are most often written can be moved to RAM, to do this, add the following lines to the end of the /etc/fstab file:
tmpfs /tmp tmpfs rw,size=100m 0 0
tmpfs /run tmpfs rw 0 0
tmpfs /var/lock tmpfs rw 0 0
tmpfs /var/log tmpfs rw,size=10m 0 0
The kernel does not immediately write data to disk, but caches it in memory, and writes it when the disk is not loaded or it can no longer be stored in memory. To configure settings for flushing data to disk, use the files /proc/sys/vm/. The settings below reduce the number of entries by increasing RAM consumption.
Maximum time between data writes to disk:
sudo sysctl -w vm.laptop_mode=120
$ sudo sysctl -w vm.dirty_writeback_centisecs=12000
$ sudo sysctl -w vm.dirty_expire_centisecs=12000
Maximum amount of cache memory in percentage:
sudo sysctl -w vm.dirty_ratio=10
Write data to disk when only % of memory is free:
sudo sysctl -w vm.dirty_background_ratio=1
After these settings installing ubuntu to the flash drive is completed, the system is more or less ready for use on the flash drive and will not harm it that much. But still don't forget to do it from time to time backups important data, because everything can break down at the most inopportune moment.
